forked from 1b-agent/opencadstudio-upstream
BlockEntityAdd adds a validated entity to a block definition (owner set by the host, same validation as a model-space entity, self-nesting inserts refused), reusing the scene's block-editor routing. Deleting a block member now also drops its handle from the block record. Real-IPC audit with an attribute definition inside a block, DWG/DXF persistence and undo; IPC and Python unit tests; docs. Co-Authored-By: Claude Sonnet 5 <[email protected]>